The present invention relates to a sliding track assembly for drawers, and relates more particularly to such a sliding track assembly which can be conveniently installed by an automatic mounting machine without the use of any rivet.
Figures from 1 to 4 show a sliding track assembly for drawers according to the prior art, which is generally comprised of an outer rail for fastening the inside wall of the cabinet, table, desk, etc., an intermediate rail, an inner rail for fastening to the drawer at one lateral side, a first sliding ball rack slidably connected between the outer rail and the intermediate rail, a second sliding ball rack slidably connected between the intermediate rail and the inner rail, a stop plate fixedly secured to the outer end of the intermediate rail, and a pawl turned about a pivot on the inner rail. This structure of sliding track assembly is still not satisfactory in function. When the drawer is pulled out of the cabinet, the pawl tends to be deformed by the stop plate. When the inner rail is inserted into the intermediate rail, the pawl will be squeezed by the stop plate, therefore the stop plate and the pawl wear with use quickly. When the pawl or the stop plate has begun to wear, the inner rail will disconnect from the intermediate rail when the drawer is pulled out of the cabinet. Because the pawls of the two sliding track assemblies at two opposite sides of the drawer must be turn ed in different directions so that the drawer can be disconnected from the cabinet, the parts of the sliding track assemblies may be damaged when the pawls are not turned correctly. Furthermore, when inserting the inner rail into the intermediate rail, the inside end of the inner rail may be stopped against the outer end of the second sliding ball rack, causing the second sliding ball rack to be damaged or the inner rail unable to be inserted into position.
Figures from 5 to 13 show another structure of sliding track assembly for drawers according to the prior art, which is generally comprised of an outer rail for fastening to the inside wall of the cabinet, table, desk, etc., an intermediate rail, an inner rail for fastening to the drawer at one lateral side, a first sliding ball rack slidably connected between the outer rail and the intermediate rail, a second sliding ball rack slidably connected between the intermediate rail and the inner rail, a first stop plate fixedly secured to the outer end of the intermediate rail, and a second stop plate fastened to the inner rail by rivets. This structure of sliding track assembly also has draybacks. One drawback of this structure of sliding track assembly is that the second stop plate tends to displace. If the second stop plate is not disposed in parallel with the inner rail perfectly, the inner rail tends to disconnect from the intermediate rail when the drawer is pulled out of the cabinet. Another drayback of this structure of sliding track assembly is the complicated mounting process of the second stop plate. Still another drawback is that the inside end of the inner rail may be stopped against the outer end of the second sliding ball rack when inserting the drawer into the cabinet. If the inside end of the inner rail is stopped against the outer end of the second sliding ball rack, the drawer cannot be inserted into position. If the drawer is forced into position, the second sliding ball rack will be damaged.
The present invention has been accomplished to provide a sliding track assembly for drawers which eliminates the aforesaid drawbacks.
According to one aspect of the present invention, the sliding track assembly comprises an outer rail securely fixed to the inside wall of a cabinet, an intermediate rail, an inner rail fixedly secured to a drawer at one lateral side, a first sliding ball rack slidably connected between the outer rail and the intermediate rail, and a second sliding ball rack slidably connected between the intermediate rail and the inner rail, a first stop plate fixed to the intermediate rail at an outer end and having two projecting blocks for engagement with a second stop plate on the inner rail and two stop rods for stopping the second sliding ball rack in place, a second stop plate fixed to the inner rail at an outer side to engage with the projecting blocks of the first stop plate so as to stop the drawer in place when the drawer is pulled out of the cabinet, wherein the second stop plate has a projecting block at one end fitted into a locating hole on the inner rail, a forked tail fastened to a retainer rod on the inner rail, a retaining portion suspended between the projecting block and the forked tail for engagement with the projecting blocks of the first stop plate, and a press portion connected between the retaining portion and the forked tail and depressed to disengage the retaining portion from the projecting blocks of the first stop plate for allowing the drawer to be disconnected from the cabinet.
According to another aspect of the present invention, the first stop plate has two stop rods with a respective projecting portion. When the drawer is moved out of the cabinet and disconnected from it, the projecting portions are stopped at a respective projecting portion on the second sliding ball rack. Therefore, when the drawer is inserted into the cabinet again, the front end of the inner rail can be smoothly moved over the stop rods into the second sliding ball rack without being constrained by the projecting portions of the second sliding ball rack.
According to still another aspect of the present invention, the inner rail has a through hole corresponding to the retaining portion of the second stop plate, therefore the retaining portion can be forced to curve into the through hole on the inner rail and to disengage from the projecting blocks of the first stop plate when the press portion of the second stop plate is depressed.
According to still another aspect of the present invention, the first stop plate is made from plastics, having an arched front end projecting out of the intermediate rail, therefore when the drawer is moved out of the cabinet or pushed back inside the cabinet, little noise will be produced.